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| author | Arnd Bergmann <arnd@arndb.de> | 2015-11-26 01:47:38 +0300 |
|---|---|---|
| committer | Arnd Bergmann <arnd@arndb.de> | 2015-11-26 01:47:38 +0300 |
| commit | d3de94ba4e58e8043d500f7335797d6a2ac93248 (patch) | |
| tree | 8382a170965eec00ebfe62e7b42dfdea9ca44f54 /drivers/usb/host/xhci.c | |
| parent | fabc2c9c1ff5376489e83e142f1ab236609435b1 (diff) | |
| parent | 1ec218373b8ebda821aec00bb156a9c94fad9cd4 (diff) | |
| download | linux-d3de94ba4e58e8043d500f7335797d6a2ac93248.tar.xz | |
Merge tag 'v4.4-rc2' into fixes
Linux 4.4-rc2 is backmerged from the keystone fixes.
Diffstat (limited to 'drivers/usb/host/xhci.c')
| -rw-r--r-- | drivers/usb/host/xhci.c | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c index 6e7dc6f93978..dfa44d3e8eee 100644 --- a/drivers/usb/host/xhci.c +++ b/drivers/usb/host/xhci.c @@ -175,6 +175,16 @@ int xhci_reset(struct xhci_hcd *xhci) command |= CMD_RESET; writel(command, &xhci->op_regs->command); + /* Existing Intel xHCI controllers require a delay of 1 mS, + * after setting the CMD_RESET bit, and before accessing any + * HC registers. This allows the HC to complete the + * reset operation and be ready for HC register access. + * Without this delay, the subsequent HC register access, + * may result in a system hang very rarely. + */ + if (xhci->quirks & XHCI_INTEL_HOST) + udelay(1000); + ret = xhci_handshake(&xhci->op_regs->command, CMD_RESET, 0, 10 * 1000 * 1000); if (ret) |